html, body {
    margin: 0;
    padding: 0;
    height: 100%; /* 关键：确保高度占满屏幕 */
  }
  
  html {
    background: linear-gradient(to bottom right, #af441a, #dcaf30);
    background-attachment: fixed; /* 防止滚动时重复 */
    background-repeat: no-repeat; /* 禁止重复 */
    background-size: cover; /* 拉伸覆盖全屏 */
  }

.navbar_ul {
    z-index: 1000;
    position: fixed;
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333;
    position: fixed;
    top: 0;
    width: 100%;
}

.navbar_li {
    float: left;
}

.navbar_li a {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

.navbar_li a:hover:not(.active) {
    background-color: #111;
}

.active {
    background-color: #fd8700;
}

.footer {
    position:static;
    left: 0;
    bottom: 0;
    width: 100%;
    background-color: #333;
    color: white;
    text-align: center;
    padding: 10px 0;
    transform: scale(1.2);
    font-size: 0.8em;
}

.white_text {
    color: #f0f0f0;
}

/*
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background: linear-gradient(135deg, #1a2a6c, #b21f1f, #1a2a6c);
    background-size: 400% 400%;
    animation: gradientBG 15s ease infinite;
    color: #fff;
    min-height: 100vh;
    padding: 20px;
}
*/

@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* 弹性布局容器 */
.flex-container {
    display: flex;
    flex-wrap: wrap;
    gap: 25px;
}

.card {
    flex: 1;
    min-width: 200px;
    max-width: 350px;
}

/* 大屏幕布局 - 横向排列 */
@media (min-width: 1200px) {
    .flex-container {
        flex-wrap: nowrap; /* 防止换行 */
    }
}

/* 中等屏幕布局 - 两列 */
@media (min-width: 768px) and (max-width: 1199px) {
    .card {
        flex: 1 0 calc(50% - 25px);
        max-width: calc(50% - 25px);
    }
}

/* 窄屏布局 - 纵向排列 */
@media (max-width: 767px) {
    .flex-container {
        flex-direction: column;
    }
    .card {
        width: 100%;
        max-width: 100%;
    }
}

/* 卡片样式 */
.card {
    background: rgba(255, 255, 255, 0.12);
    border-radius: 16px;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.18);
    padding: 30px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
    background: rgba(255, 255, 255, 0.18);
}

.card-icon {
    font-size: 3.5rem;
    margin-bottom: 20px;
    text-align: center;
    color: #ff7e5f;
}

.card h3 {
    font-size: 1.8rem;
    margin-bottom: 15px;
    color: #ffb47b;
    text-align: center;
}

.card p {
    font-size: 1.1rem;
    line-height: 1.7;
    color: #e0e0ff;
    margin-bottom: 20px;
}

.card ul {
    padding-left: 20px;
    margin-bottom: 25px;
}

.card li {
    margin-bottom: 10px;
    color: #e0e0ff;
}

.btn {
    display: block;
    width: 100%;
    padding: 14px;
    background: linear-gradient(to right, #ff7e5f, #feb47b);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
    text-decoration: none;
}

.btn:hover {
    background: linear-gradient(to right, #ff6b4a, #ff9e6d);
    transform: scale(1.03);
    box-shadow: 0 4px 15px rgba(255, 126, 95, 0.4);
}

.container a {
    text-decoration: none
}